In any of the newspaper databases, you have the option to avoid articles from certain sections. Here's a sample search from Access World News. In the third line of my search, I'm telling the database that I do NOT want to see results from a section called Editorial or Opinion or Commentary (newspapers have different names for this section).
In Nexis Uni, after you populate the "Headline and Lead Sections" box with your search word(s), type "editorial or commentary or opinion" into the "Section" box. Finally, add the word "NOT" to your search string at the top of the page so that content from those sections is excluded.
